title: Female Drosophila melanogaster gene expression and mate choice: the X chromosome harbours candidate genes underlying sexual isolation.
abstract: BACKGROUND
  The evolution of female choice mechanisms favouring males of their own kind is considered a crucial step during the early stages of speciation. However, although the genomics of mate choice may influence both the likelihood and speed of speciation, the identity and location of genes underlying assortative mating remain largely unknown.
  
  
  RESULTS
  We used mate choice experiments and gene expression analysis of female Drosophila melanogaster to examine three key components influencing speciation. We show that the 1,498 genes in Zimbabwean female D. melanogaster whose expression levels differ when mating with more (Zimbabwean) versus less (Cosmopolitan strain) preferred males include many with high expression in the central nervous system and ovaries, are disproportionately X-linked and form a number of clusters with low recombination distance. Significant involvement of the brain and ovaries is consistent with the action of a combination of pre- and postcopulatory female choice mechanisms, while sex linkage and clustering of genes lead to high potential evolutionary rate and sheltering against the homogenizing effects of gene exchange between populations.
  
  
  CONCLUSIONS
  Taken together our results imply favourable genomic conditions for the evolution of reproductive isolation through mate choice in Zimbabwean D. melanogaster and suggest that mate choice may, in general, act as an even more important engine of speciation than previously realized.
authors.affiliation: Department of Ecology and Genetics, Evolutionary Biology Centre, Uppsala University, Uppsala, Sweden.
authors.forename: Richard I
authors.initials: RI
authors.lastname: Bailey
authors.forename: Paolo
authors.initials: P
authors.lastname: Innocenti
authors.forename: Edward H
authors.initials: EH
authors.lastname: Morrow
authors.forename: Urban
authors.initials: U
authors.lastname: Friberg
authors.forename: Anna
authors.initials: A
authors.lastname: Qvarnström
mesh_terms: D000818:Animals; D002755:Choice Behavior / Q000502:physiology; D002874:Chromosome Mapping; D016000:Cluster Analysis; D004331:Drosophila melanogaster / Q000235:genetics* / Q000502:physiology*; D005260:Female; D005786:Gene Expression Regulation; D050172:Genes, X-Linked / Q000502:physiology*; D056726:Genetic Association Studies; D008297:Male; D008954:Models, Biological; D011995:Recombination, Genetic / Q000502:physiology; D012727:Sex Characteristics; D012726:Sexual Behavior, Animal / Q000502:physiology*; D012934:Social Isolation; D014960:X Chromosome / Q000235:genetics / Q000502:physiology